The England international is currently enjoying some free time before returning to the Premier League club for pre-season training.
Last year, the 22-year-old sparked controversy after he was caught puffing on a cigarette outside of a nightclub and later insisted that he is unlikely to smoke again.
However, the midfielder appears to have gone back on his word after photographs emerged of him smoking while surrounded by friends in a swimming pool at a Vegas resort.
Wilshere was also joined by Manchester City and England goalkeeper Joe Hart while in Sin City.
Jack Wilshere pictured smoking. pic.twitter.com/sUmTmpwys2— Arsenal FC (@FFArsenal) July 14, 2014